Prostate Cancer Risk, Aggressiveness Tied to Socioeconomics

Study of Canadian men looked at the association between prostate cancer and participants’ socioeconomic position during childhood/adolescence and early and late adulthood.

Disadvantageous socioeconomic position (SEP) over the course of a man’s lifetime is associated with a greater likelihood of developing prostate cancer (PCa), with consistent evidence of sensitive time periods for cancer aggressiveness, according to Canadian researchers.

A team led by Marie-Élise Parent, PhD, of the Epidemiology and Biostatistics Unit, INRS-Institut Armand-Frappier, Université du Québec, Quebec, Canada, examined data from the Prostate Cancer & Environment Study (PROtEuS), a population-based case-control study that included 1930 PCa patients in Montreal. All the men were diagnosed with histologically-confirmed PCa from 2005 to 2009. The investigators identified 1991 men to serve as controls. All study participants were interviewed in-person, and information was gathered on socio-demographic and lifestyle characteristics, along with a complete occupational history.

The researchers measured SEP during childhood/adolescence by looking at parents’ ownership of a car and a father’s longest occupation. Study subjects’ first and longest occupation was used to indicate early- and late-adulthood SEP, respectively.

Cumulative exposure to disadvantageous SEP was associated with about a 50% increase in the odds of developing PCa, Dr Parent’s team reported on Frontiers in Oncology. Late-adulthood SEP was a sensitive period for aggressive PCa, independent of PCa screening. Childhood/adolescence SEP based on parents’ ownership of a car was associated with non-aggressive PCa, independent of PCa screening.

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The authors noted that previous investigations into PCa risk and SEP have produced contradictory results. These earlier studies mostly measured SEP only once during individuals’ lifespan. The current study was designed to identify the relationship between SEP measured during childhood/adolescence, early-adulthood, and late-adulthood, and risk of PCa overall according to tumor aggressiveness at diagnosis.

Dr Parent and her colleagues reported that SEP represents an umbrella of factors that may collectively influence PCa burden, including behavioral and environmental risk factors as well as access to health care. Mounting evidence suggests that favorable SEP is associated with better overall survival among PCa patients, according to the authors.

The prostate gland is essentially dormant until puberty. At that time, a complex interaction between sex and other growth hormones induces rapid prostate gland development, Dr Parent’s team explained. Adolescence is a rapid time of profound change in hormone levels and body composition. It is theorized that early-life SEP could shape the environment during this important developmental window of vulnerability and increase PCa risk. It is also hypothesized that environmental exposures in specific periods of life may affect tumor aggressiveness.

Aggressive PCa appears to have different sets of anthropometric, lifestyle, and occupational risk factors. “This raises the possibility that aggressive cancers represent a specific etiological entity, possibly developing under exogenous influences that operate at a specific time over the life course,” the investigators wrote.

This study has significant advantages owing to its large sample size, the quality of job history information, and the inclusion of different indicators of SEP at 3 time points.

These findings will require further validation and suggest a need for a more detailed exploration into the mechanisms through which disadvantageous SEP affects prostate cancer risk during different exposure periods. It is hoped that these types of investigation will lead to new prevention strategies.

Alexander Kutikov, MD, Professor and Chief of Urologic Oncology at Fox Chase Cancer Center in Philadelphia, said that although the new study included large number of patients, it has some inherent limitations. “Studies of the relationship between prostate cancer outcomes and socioeconomic status are notoriously challenging,” said Dr Kutikov, who serves as editor of the Prostate Cancer Advisor section of Renal & Urology News. “Numerous measured and unmeasured confounders usually stand in the way to identifying meaningful relationships. This is a study of a very narrow patient population in Montreal, Canada. Of course, its generalizability is uncertain.”

Mark Garzotto, MD, Professor of Urology at Oregon Health and Science University in Portland, said this current study is interesting and timely. The authors show a clear relation to SEP and both PCa incidence and aggressiveness. “The method of data collection allowed for the exploration of the time effect of SEP, which had not been done previously to this depth,” Dr Garzotto said. “This study is of particular interest as global income disparities continue to rise and the downstream effects on health become more relevant. Exploration into the causes of these disparate effects are of great interest to the oncologic research community.”